Saul recently shared his thinking on malt. I've been spending a lot of time lately thinking about another essential ingredient in beer. Hops. While in the UK, I had the opportunity to visit four hop farms, a hop research facility, and a hop merchant- all within a week! My head is still spinning.
My tour de hops started in Canterbury, Kent. This was an appropriate place to begin because it is not only a historic hop growing region, but also the home of Wye Hops, Ltd., a hop research center and subsidiary of the British Hop Association. Wye Hops carries on the pioneering hop breeding program of Wye College, an agricultural school that sadly closed in 2006.
If you love hops, beer, or most especially hoppy beer, you should know about Wye College. It's highly likely that you have enjoyed a brew made with hops that owe at least partial parentage to varieties developed at Wye. Without Wye College, there would be no Centennial, Citra, Crystal, Sorachi Ace, Nugget, Galena, Magnum, and many others. The list goes on and on.
The influence of Wye College's breeding program extends far beyond their specific varietal legacy. Why? Because Wye College, specifically Professor E. S. Salmon, the scientist who founded its breeding program in 1906, revolutionized modern hop breeding. It is not a stretch to say that Salmon lay the groundwork for all 20th century hop breeding. I had the chance to learn more directly from Dr. Peter Darby, head of Wye Hops, Ltd. and, from 1984 until its closing, the third and final head of the breeding program at Wye College. He carries on the torch!
The morning I arrived at Wye Hops, Dr. Darby gave me a simplified botanical history of hops to contextualize Salmon's achievement. I'll do the same here.
Hops, humulus lupulus, come from central China. Some spread west to Europe. Some spread east to Japan and North America. The Asian and North American hops tended to split and split. They had huge genetic diversity. The European hops were more stable with far less diversity. Now, fast forward to Kent at the start of the 20th Century. Hops had already been cultivated here for over 350 years! It had long been understood that some individual hop plants had better qualities for brewing than others. Growers practiced methods of selecting and propagating superior plants. As a result, many grower-selected varieties were established, such as Mr. Fuggle's hop and Mr. Golding's hop, later called Fuggles and Goldings. At the same time, breeding programs utilizing the "new" science of genetics were popping up in hop-growing countries in response to demands from growers and brewers.
The conventional breeding practice at the time was to cross the best individuals from established varieties. The thinking was that crossing the best with the best would lead to something even better. Salmon, however, bucked this orthodoxy and did something revolutionary that took hop breeding in a whole new direction. He crossed an open pollinated British hop with a wild North American hop. In the scientific community, this was practically heresy! How could a wild hop, from North America no less, produce a superior offspring? Salmon was doing something completely new in hop breeding. Brilliantly, he reunited the genetic material of the western and eastern split-offs. Salmon realized that more genetic material meant more opportunities to breed for higher alpha acid content, desirable aromas, increased yield, and pest and disease resistance.
Diversity is a beautiful thing!
Using his innovative techniques, Salmon went on to develop three principal varieties: Brewer's Gold (1934), Bullion (1938), and Northern Brewer (1944). It can be estimated that over 50% of today's world hop acreage comprises varieties derived from these three varieties. Professor Salmon was clearly onto something! Today, crossing commercial varieties with wild varieties is a standard hop breeding practice.
An interesting side note. A similar reunion of the western and eastern genetics
occurred by chance early in US hop growing history with Cluster, the
historic hop of New York State back when we were the center of US hop
production. Cluster came about when European hops brought over in the 17th century crossed with native North American wild hops. Another successful genetic reunion, until powdery mildew hit!
Digesting Salmon's fascinating story and marveling at the history of British hop breeding and its lasting impact on hops and beer worldwide was how my day in Canterbury began. This story was covered in just the first half hour of two days with Peter Darby, an absolute wealth of information. The day continued with a tour of China Farm, the commercial hop farm which houses Wye Hops and its experimental hop garden. I saw Dr. Darby's 2009-2011 crosses in the field. I saw the official National Hop Collection, also located on China Farm. It contains over 120 named varieties and represents 200-300 years of British hop growing history. Just the beginnings of shoots were visible in the fields, but it was still impressive to see.
Next, we visited the greenhouse where Wye Hops starts its experimental crosses. Currently, there are 18,000 genetically unique seedlings in the greenhouse. In their quest for disease-resistant varieties, Dr. Darby and his team systematically expose the seedlings to downy mildew. This brings their numbers down to 3000 healthy seedlings. Next, the remaining seedlings get a powdery mildew treatment, which further reduces their numbers to 1400 viable seedlings. As we inspected the seedlings, Dr. Darby mentioned how "inbreeding" is common in hop breeding. Mother-son crosses and brother-sister crosses can produce odd but desirable results. Citra is an example of a successful brother-sister cross. Dr. Darby had employed this technique with some of the crosses in front of us.
Touring the Wye Hops enterprise that morning, I felt like the luckiest novice hop grower in the world! It was the beginning of many fruitful days of learning about this alluring climbing plant. My hope is to gradually translate all the information I amassed into useful bites for the (re)emerging New York hop industry, including our own little Onondaga County hop farm currently in the making.